Polyfunctional polymers as deinking agents

ABSTRACT

This invention presents a series of polyfunctional polymers useful as deinking agents. The polymers, which generally have molecular weights in the 2,000-100,000 range, can be used to effectively separate and remove ink in a variety of deinking processes, including flotation, wash, and mechanical, resulting in fibers of superior brightness.

This is a divisional of copending application Ser. No. 07/563,887 filedon 6 Aug. 1990 pending, which is a continuation of application Ser. No.07/330,651 filed on 30 Mar. 1989 and now abandoned.

BACKGROUND OF THE INVENTION

In the past few decades, as both timber resources and available landfillsites have greatly diminished, the demand for recycling of printedpapers, especially newsprint, has skyrocketed. Such recycling effortshave been aimed at developing processes whereby previously-used paperscan be reprocessed and recycled for use. A major objective of suchprocesses is the recovery of fibers which possess the physicalproperties and brightness of more expensive virgin pulp. End useconsiderations also play a major role in determining which parametersare critical for efficient recycling. Thus, for example, in newsprintink holdout is of primary importance while in tissue, removal of fillersis critical to obtain a final product of satisfactory softness.

One major obstacle to the efficient recycling of such papers is thedifficulties encountered in removing the ink from the printed paperbefore, during, or after the pulping process. This has becomeparticularly difficult with newly developed inks and printing processes,which result in a much more tightly bound ink to the fibers. Improveddeinking agents are needed to expand the utility of the deinkingprocess.

The deinking process and deinking agents have been discussed in manyarticles (see e.g. Crow and Secor, Tappi Journal, July 1987, pp 101-100;Wasilewski, 1987 Pulping Conference Proceedings, pp 25-31; McCool andSilveri, 1987 Pulping Conference Proceedings, pp 33-39; and Gilkey etal., 1987 Pulping Conference Proceedings, pp 133-141). Briefly, all suchprocesses involve the removal of the ink from the recycled paper by useof deinking agents such as detergents or surfactants, and the subsequentseparation of this removed ink from the pulp. This separation isaccomplished by washing, wherein the ink is dispersed in the aqueoussystem and removed with the water using mechanical processes such ascentrifugation or screening, by flotation, wherein the ink is suspendedin the aqueous system made hydrophobic, and subsequently "floated" awayfrom the pulp in a froth (the froth is then drawn out of the system by avacuum or mechanical overflow system), by mechanical means(flocculation, screening, centrifugation, etc.) or by a combination ofthese processes. Since none of these systems will completely remove allof the ink, the deinking agents must also contain compounds orfunctional groups which prevent redeposition of the removed ink on thecleaned fibers.

To date, deinking agents used in these processes have not satisfactorilyfulfilled all these functions. For example, U.S. Pat. No. 4,518,459,Canadian Pat. No. 1,009,804. German Patent No. 2,903,150 and JapanesePatent Nos. 51,892/80, 117,690/82, 59,990/84, 155,794,85 and 117,690/82disclose conventional detergents, and surfactants for use in deinking,whereas the use of a combination of surfactants and polymers isdescribed in Japanese Pat. Nos. 75,889/86 and 85,089/87 and UK Pat.Application GB 2,178,079A (published Feb. 4, 1987). The mixtures producea satisfactory gain in brightness of the pulp, but the pulp stillcontain residual ink, including large spots, which renders the pulpunsuitable for use in many applications.

Further, as new printing ink formulations and printing processes aredeveloped, and the demand for recycling other types of waste papers(including films, foil coated papers, and pulp-colored papers)increases, there exists a real need for improved deinking agents whichcan effectively remove the printed ink from these furnishes.

SUMMARY OF THE INVENTION

It is an object of this invention to provide improved deinking agentswhich are capable of effectively removing ink from a recyclable paperleaving ink-free pulp suitable for incorporation in applicationsrequiring high grade papers. It is further an object of this inventionto provide deinking agents which can be used with a variety of printedmedia, including films, foil-coated papers, and pulp-colored papers.

The above and related objects are realized by the deinking agents ofthis invention, which are polyfunctional polymers of the two generalformulas. The first formula is ##STR1## wherein: ##STR2## R₃ =H, orbranched or straight chain C₁ -C₂₂ alkyl or alkylphenol

R₄ is H or C₁ -C₄ alkyl; ##STR3## (wherein R₅ is C₁ -C₄ alkyl orphenyl); W and Y=H or C₁ -C₄ alkyl; and ##STR4## (wherein M is ammoniumor alkali metal, R₆ is C₁ -C₄ alkyl, and x is an integer of at least 1);or ##STR5## (wherein M is ammonium or alkali metal). When Z is the lastcompound, Y and W are preferably H and CH₃, respectively. In the aboveagents: a and b are both positive integers of at least one and the ratioof a/b is 1/100 or greater; n is a positive integer of 10-100 and m=0-50wherein the ratio of n/m is 1.5/1 or greater if m is not 0.

The second formula is ##STR6## wherein ##STR7## R₇ =C₆ -C₂₂ straight orbranched chain alkyl or alkyl phenol and R₄, W, Y, Z, a, and b are asabove.

These agents are prepared by the reaction of an ethylenicallyunsaturated monomer with at least one surfactant macromonomer orhydrophobic monomer, and typically have molecular weights in the rangeof 2,000-100,000. Such agents can be added to the paper recyclingmixture before, during, or after the pulping process, and are generallyused at a treatment levels of 0.05%-1% (by weight based on the weight ofdry pulp). These agents can be used in the flotation and wash andmechanical separation deinking processes, and will result in pulp ofexceptional brightness, regardless of the deinking process used.

DETAILED DESCRIPTION OF INVENTION

The polyfunctional deinking agents of this invention comprise copolymersof ethylenically unsaturated monomers of the anionic type and one ormore functional macromonomers. The macromonomers fall within three broadclasses and, thus, the deinking agents comprise three classes ofcompounds.

Regardless of the class, the anionic-type ethylenically unsaturatedmonomers are of the following formula: ##STR8## wherein: W, Y are H orC₁ -C₄ alkyl

Z is selected from ##STR9## (in which case Y═H, and W═CH₃) wherein: R₆is C₁ -C₄ alkyl, x is a positive integer of at least 1.

W and Y can be the same or different and are preferably H or CH₃. Z ispreferably ##STR10## and M is preferably sodium (Na).

In the first class of deinking agents, the ethylenically unsaturatedmonomer of the anionic type of copolymerized with at least onesurfactant macromonomer. The surfactant macromonomers have one of thethree following formulas: ##STR11## wherein: R is C₃ -C₂₂ alkenyl orcarboxy alkenyl;

R₄ is H or C₁ -C₄ alkyl;

R₅ is C₁ -C₄ alkyl or phenyl. ##STR12## wherein: R₅ is the same asabove;

R₃ is H or straight or branched chain C₁ -C₂₂ alkyl or alkylphenol;

Y is H or C₁ -C₄ alkyl. ##STR13## wherein R₅, R₃ are the same as above.

In all of the above:

n is a positive integer of 10-100, preferably 20-50.

m is O or a positive integer of 0-50, preferably 4-20.

n/m is at least 1.5 when m≠0, preferably 2-3.

In this class of polymers, the amount of surfactant macromonomercopolymerized with the ethylenically unsaturated monomer is at least10%, by weight, preferably 25-60%.

In the second class of functional polymers contemplated by thisinvention, the polymers are produced by the copolymerization of at leastone (1) hydrophyllic surfactant macromonomer, at least one (1)hydrophobic monomer, and at least one (1) ethylenically unsaturatedvinyl monomer of the anionic type.

The hydrophyllic surfactant macromonomers are of the three followingformulas: ##STR14## wherein R=C₃ -C₂₂ alkenyl or carboxy alkenyl

R₅ is C₁ -C₄ alkyl or phenyl. ##STR15## wherein R₃ is H or C₁ -C₂₂straight or branched chain alkyl or alkyl phenol and R₅ is as above.##STR16## wherein Y═H or C₁ -C₄ alkyl an R₅ is as above.

The hydrophobic monomers are of the four following formulas: ##STR17##wherein R, R₅, and Y are as above,

R₃ ' is C₁ -C₂₂ straight or branched chain alkyl or alkylphenol,

R₄ ' is C₁ -C₄ alkyl and R₇ is C₆ -C₂₂ straight or branched alkyl.

In this class of polymers, m and n are as defined above, the amount ofhydrophobic monomer copolymerized is at least 1% by weight and theamount of hydrophyllic macromonomer copolymerized is at least 10% byweight. Preferably, the polymers comprise 2-5% hydrophobic monomer and20-60% hydrophyllic macromonomer.

The third class of functional polymers contemplated by this inventioncomprises copolymers of at least one (1) hydrophobic macromonomer and atleast one (1) ethylenically unsaturated monomer of the anionic type. Thehydrophobic monomers are of the same formulas as the hydrophobicmonomers of the second class and n and m are as in the first class. Theamount of hydrophobic macromonomer copolymerized with the ethylenicallyunsaturated monomer is at least 1% by weight preferably 5-15%.

Regardless of the monomers used, the polymers produced have a molecularweight of at least 2000, preferably 5000-40,000. It is recognized,however, that the molecular weights can be increased as the particularapplications dictate and, specifically, that polymers having molecularweights well in excess of 100,000 can be produced and utilized indeinking processes. The polymers can be produced by any convenientaqueous polymerization method, including solution polymerization in thepresence of a suitable cosolvent, micellar polymerization, or emulsionpolymerization. It is further contemplated that graft copolymerizationmethods can also be used to obtain functional polymers suitable for usein deinking. The actual method used will be dictated by personalpreference, material availability and activity, as well as theproperties of the particular monomers utilized.

The polymer produced can be used in any conventional deinking processincluding flotation, wash, and mechanical separation. Regardless of theprocess used, the polymer is added at a convenient time during thedeinking process. Treatment levels range from 0.001 to 1% (by weightbased on weight of dry pulp), preferably 0.01 to 0.7% by weight.However, these levels can vary depending upon the particular processemployed, the particular furnish, and the particular functional polymer.

The functional polymers of this invention can be used with any furnisheswhich are commonly recycled (such as newsprint), as well as otherfurnishes such as laser printed papers, flexographic printed papers,pulp colored papers, foil-coated papers, plastic coated papers, etc. Alist of commonly recycled papers is presented in circular PS-86 of thePaper Stock Institute of America (April, 1986, pp 4-8) incorporatedherein by reference.

EXAMPLES

The following examples illustrate certain preferred embodiments of thisinvention and are not intended to be illustrative of all embodiments.

Example I Preparation of Deinking Polymers

Representative deinking polymers of this invention were prepared asdescribed below.

Polymer A

In this example, a functional polymer comprising a surfactantmacromonomer, monomethacrylate PEG 2000, and a vinyl monomer (acrylicacid) was prepared.

Briefly, a mixture of 450 g-deionized water and 20 g of isopropylalcohol was charged to a 2 liter glass reactor equipped with a refluxcondenser, stirrer, thermometer and two inlet ports for the addition ofmonomer and catalyst. After the mixture was refluxed for 10 minutes at90° C., 300 g of a monomer mixture, comprising 100 g each of acrylicacid, monomethacrylate PEG (polyethylene glycol) 2000 (approx. 40 EO,mol wt.=2000) and deionized water, and 80 g of 1.875% aqueous sodiumpersulfate solution were continuously pumped into the reactor while thetemperature was maintained at about 90±2° C. The system was thenincubated at 90±2° C. for an additional 30 minutes, after which a 40 gcharge of 2.5% aqueous sodium persulfate was added. The reaction mixturewas subsequently maintained at 90+2° C. for an additional hour, and thenneutralized to pH 7 with 50% caustic soda. The neutralized product wassubsequently vacuum distilled, removing 70 g of distillate, and leavingviscous, clear straw-colored liquid product, with a solids content of29.7% and a pH of about 7.0. The polymer produced had a weight averagemolecular weight (M.W.) of about 100,000 (as measured by gel permeationchromatography using sulfonated polystyrene as the standard). This wasretained as Polymer A.

Polymer B-1 and B-2

In this example, a second functional polymer containing allyl alcoholethoxylate (24 EO) and acrylic acid was prepared. Briefly the procedurefollowed was identical to that used in the preparation of Polymer A,except that the acrylic acid/allyl alcohol ethoxylate (24 EO) ratio was80/20. Two preparations were made, differing in the amount of catalystused. The products obtained had solids contents of 27.5% and 29.7% andrespective weight average molecular weights of 75,000 (B-1) and 25,000(B-2).

Polymer C

In this example, a functional polymer containing acrylic acid and allylalcohol ethoxylate (44 EO) was prepared following the procedure ofPolymer A. The weight ratio of acrylic acid to allyl 44 EO was 80/20.

The product had a solid content of 31% and a weight average molecularweight of 23,000.

Polymer D-1 and D-2

In this example, functional polymers derived from two anionic vinylmonomers (acrylic acid and maleic acid) and a hydrophobic monomer(t-octylacrylamide) were prepared. The formulations were as follows:

    ______________________________________                                        Material             D-1           D-2                                        ______________________________________                                        A.    toluene            250    g    250  g                                         maleic anhydride   49.1   g    49.1 g                                   B.    toluene            70     g    70   g                                         acrylic acid       71.5   g    69.9 g                                         t-octyl acrylamide 1.4    g    5.5  g                                   C     toluene            35     g    35   g                                         benzoyl peroxide   2.4    g    2.4  g                                   D     distilled water    400    g    400  g                                         aqueous NaOH (25% W/V)                                                                           230    ml   230  ml                                  ______________________________________                                    

Initially, the A part was charged to a 2 liter flask equipped with athermometer, two addition funnels, stirrer, thermometer, and refluxcondenser, and the system was heated to reflux; subsequently B and Cwere both slowly added simultaneously (B over 3 hours, C over 5 hours)with stirring. Once the addition was complete, the system was refluxedan additional 2 hours (a precipitate formed during this time), afterwhich D was added. The toluene was then steam stripped from the system,and the pH was adjusted to 7.0-7.5.

Product D-1 had a solids content of 15.4% and a weight average molecularweight of 24,400, while D-2 had a solids content of 19.4% and amolecular weight of 20,200.

Polymer E

In this example, functional polymers derived from a surfactant monomer(allyl alcohol ethoxylate, 44 EO), a hydrophobic monomer (tridecylmethacrylate) and an anionic vinyl monomer (acrylic acid) were prepared.Briefly, a mixture of 450 g deionized water and 150 g n-propanol wascharged to a 2 liter glass reactor equipped with a reflux condenser,stirrer, thermometer and two inlet ports for the addition of monomersand catalyst. After the mixture was refluxed for 10 minutes, a monomermixture (comprising 135 g acrylic acid, 44 g allyl alcohol ethoxylate,40 g deionized water, and 5 g tridecyl methacrylate) and 80 g of 1.25%sodium persulfate solution were continuously pumped into the reactorsimultaneously over a period of three (3) hours, while the reactiontemperature was maintained at 85° C. The system was subsequentlyincubated at 85° C. for an additional 10 minutes after the addition wascomplete, after which 20 g acrylic acid was pumped in, followed by 20 gof 2.5% sodium persulfate solution. The system was subsequentlymaintained at 85° C. for another hour, after which the reactor contentwas cooled to about 50° C. and neutralized to pH 7 with 50% causticsoda. The neutralized product was subsequently vacuum distilled toremove 280 g distillate, 50 g of deionised water was then added to formthe final product, which was a white viscous liquid with a solidscontent of 28%. The polymer had a weight average molecular weight of39,000.

Example II Deinking Procedures

The above polymers were subjected to testing in flotation and washdeinking systems using the following procedures:

Flotation

The flotation procedure utilized a standard Wemco cell. Briefly, 1910 mlwater was heated to 40°-45° C. and charged to a Waring blender.Subsequently, the following is charged:

    ______________________________________                                        a) Sodiun Silicate                                                                              1.0 ml                                                      b) 35% Sodium Peroxide                                                                          2.8 ml                                                      c) 50% NaOH       2.0 ml                                                      d) DTPA (Kalex Penta)                                                                           0.15 ml                                                     e) Polymer        as per test                                                 ______________________________________                                    

and the system is mixed for one (1) minute. A total of 92 g paper (69 gnewsprint, 23 g magazine) is added, and the entire system is pulped inthe blender at high speed for 2 minutes, followed by low speed for 8minutes.

The resultant pulp is then diluted with 5750 ml water at 40°-45° C., andtransferred to the Wemco cell and frothed at 800 rpm for 5 minutes; thefoam is collected from the system during this time through an outlet and500 ml water is added to the system each minute to compensate for thefoam removed. The amount of foam collected (in ml) is recorded and,after drying, the amount of fiber collected is determined (this isreported as a % of total fiber).

A pulp "pad" is then formed by filtering 1 liter of pulp on a Buchnerfunnel (through #4 paper) and subsequently pressing on a steel patten.The pads are evaluated for brightness by measuring reflectance on theTechnibrite Micro TB-1C analyzer; this value is reported as a % of thereflectance of the MgO standard. This value is compared with thebrightness of the raw pulp (pulper) and the gain in brightness iscalculated. In general, the greater the gain in brightness, the betterthe degree of ink removal.

Wash

In this system, 1910 ml of water (as in the flotation procedure) ismixed with

    ______________________________________                                        a) DTPA (Kalex Penta)                                                                            1.0 ml                                                     b) Sodiun Silicate                                                                              0.85 ml                                                     c) Polymer        as per test                                                 ______________________________________                                    

for one minute. A total of 88 g newsprint is added, and the system ispulped as in the flotation procedure.

The deinked pulp is concentrated by straining through cheese cloth andmanually squeezing dry. Fifty (50) g of this pulp is diluted with 2liters of distilled water and disintegrated for 5 minutes in a standardcommercial disintegrator. One (1) liter of this mixture is then filteredon a Buchner funnel and pressed on a steel patten, as in the flotationprocedure to form a pad. The pad is examined as in the flotationprocedure.

Example III--Flotation Deinking Test

To assess the utility of the polymers of this invention in the flotationdeinking process, a variety of polymers were compared with those listedin Example I at different treatment levels. The procedure followed wasthat of the flotation described in Example II. The results are presentedin Table I.

                                      TABLE I                                     __________________________________________________________________________    Summary of Flotation Deinking Test Results                                    Brightness (TAPPI)   Fiber                                                                             Foam Treatment Level                                       After                                                                             Finished                                                                           Gain in                                                                             Loss                                                                              Collected                                                                          (% wt. based on                                 Sample                                                                              Pulper                                                                            Pulp Brightness                                                                          (%) (ml) dry pulp)                                       __________________________________________________________________________    I.sup.1                                                                             48.7                                                                              52.3 3.6   2.6 --   0.20                                            II.sup.2                                                                            51.2                                                                              55.7 4.5   3.7  850 0.20                                            Polymer A                                                                           55.3                                                                              59.6 4.3   4.5 1150 0.20                                            Polymer                                                                             54.2                                                                              57.6 3.4   4.3 1175 0.20                                            B-1                                                                           Polymer C                                                                           54.5                                                                              57.8 3.3   3.9 1000 0.20                                            Polymer E                                                                           53.4                                                                              57.8 4.4   --  --   0.20                                            I.sup.1                                                                             53.1                                                                              56.2 3.1   4.3 --   0.06                                            II.sup.2                                                                            51.2                                                                              54.6 3.4   --  --   0.06                                            Polymer A                                                                           52.6                                                                              57.8 5.2   --  --   0.06                                            Polymer                                                                             52.1                                                                              56.9 4.8   --  --   0.06                                            B-1                                                                           Polymer C                                                                           50.2                                                                              53.9 3.7   3.2 --   0.06                                            Polymer                                                                             51.7                                                                              56.1 4.4   --  1200 0.06                                            D-1                                                                           Polymer                                                                             54.0                                                                              59.2 5.2   --  1500 0.06                                            D-2                                                                           III.sup.3                                                                           52.0                                                                              56.2 4.2   4.1 1200 0.01                                            IV.sup.4                                                                            52.2                                                                              56.0 3.8   3.7 1200 0.01                                            Polymer A                                                                           53.0                                                                              57.8 4.8   5.0 1030 0.01                                            Polymer                                                                             53.1                                                                              61.0 7.9   4.6 1225 0.01                                            B-1                                                                           Polymer                                                                             50.4                                                                              55.9 5.5   --  --   0.01                                            D-2                                                                           Polymer A                                                                           50.0                                                                              58.4 8.4   4.0 1200 0.03                                            Polymer                                                                             50.7                                                                              57.8 7.1   4.3 1250 0.03                                            B-1                                                                           __________________________________________________________________________     Notes                                                                         .sup.1 A surfactant of the formula C.sub.16-18 H.sub.33-37 O (EO).sub.13      (PO).sub.6.5 H (EO = ethylene oxide, PO = propylene oxide)                    .sup.2 A commercial surfactant deinking agent.                                .sup.3 A surfactant of the formula C.sub.12-15 H.sub.25-31 O (EO).sub.9 H     .sup.4 A surfactant of the formula C.sub.12-15 H.sub.25-31 O (EO).sub.4.5     (PO).sub.7 H                                                             

As shown, it can be seen that, at low treatment levels (below 0.20%),the polymers of this invention give a much better gain in brightnessthan the commercial surfactants. This indicates that a lower amount ofdeinking agent is required to obtain good ink removal.

Since some commercial surfactants are now used in conjunction with anaccelerator or "auxilliary aid" to accomplish deinking, a series ofexperiments were conducted using such an aid, the sodium salt ofpolyacrylic acid (PAA) with commercial surfactants. The results arepresented in Table II.

Again, it can be seen that the gain in brightness produced by thepolymers of this invention is better than the gain observed withcommercial agents, with or without the accelerators, even at very lowtreatment levels.

                                      TABLE II                                    __________________________________________________________________________    Summary of Accelerator Test Results                                                         Ratio of Deinker/                                                                      Brightness (TAPPI)                                                                           Fiber                                                                             Treatment Level                                   Accel.   After                                                                             Finished                                                                           Gain in                                                                             Loss                                                                              (% by wt.) on                       Deinker                                                                              Accel. (by wt.) Pulper                                                                            Pulp Brightness                                                                          (%) dry pulp)                           __________________________________________________________________________    I      None   --       53.1                                                                              56.2 3.1   4.3 0.06                                II     None   --       51.2                                                                              54.6 3.4   --  0.06                                Polymer A                                                                            None   --       52.6                                                                              57.8 5.2   --  0.06                                Polymer B-1                                                                          None   --       52.1                                                                              56.9 4.8   --  0.06                                I      PAA    20/80    54.4                                                                              57.7 3.3   3.6 0.06                                       (2,000                                                                        M.W.)                                                                  I      PAA    20/80    54.6                                                                              58.0 3.4   3.9 0.06                                       (90,000                                                                       M.W.)                                                                  II     PAA    50/50    55.4                                                                              57.7 2.3   --  0.06                                       (2,000                                                                        M.W.)                                                                  II     PAA    80/20    51.4                                                                              54.2 2.8   --  0.06                                       (90,000                                                                       M.W.)                                                                  II     Polymer A                                                                            80/20    53.3                                                                              56.9 3.6   --  0.06                                II     Polymer B-1                                                                          80/20    54.8                                                                              57.3 2.5   --  0.06                                I      Polymer A                                                                            50/50    52.7                                                                              56.3 3.6   3.6 0.06                                I      Polymer B-.sub.--                                                                    50/50    52.6                                                                              55.4 2.8   3.5 0.06                                I      None   --       55.3                                                                              58.6 3.3   4.2 0.03                                Polymer A                                                                            None   --       50.0                                                                              58.4 8.4   4.0 0.03                                Polymer B-1                                                                          None   --       50.7                                                                              57.8 7.1   4.8 0.03                                __________________________________________________________________________

Example IV Deinking of Laser Printed Paper

To assess the utility of the functional polymers of this invention indeinking laser printed papers, experiments were conducted following theprocedure of Example III, except that laser printed paper was used. Theresults are presented in Table III.

                                      TABLE III                                   __________________________________________________________________________    Summary of Laser Print Test Results                                           Brightness (TAPPI)   Fiber                                                                             Foam Treatment Level                                       After                                                                             Finished                                                                           Gain in                                                                             Loss                                                                              Collected                                                                          (% wt. based on                                 Sample                                                                              Pulper                                                                            Pulp Brightness                                                                          (%) (ml) dry pulp)                                       __________________________________________________________________________    B-2   74.06                                                                             82.07                                                                              8.01  4.40                                                                              1100 0.20                                            C     79.95                                                                             86.97                                                                              7.02  4.66                                                                              1000 0.06                                            C     74.63                                                                             82.69                                                                              8.06  3.48                                                                              1010 0.12                                            __________________________________________________________________________

As shown, it can be seen that desirable gains in brightness areobserved, even at low treatment levels.

Example V Wash Deinking Test

To assess the utility of the polymers of this invention in a washdeinking process, Polymers A and B were compared with two commercialsurfactants following the procedure of Example II (treatment level=1.0%by wt. using newsprint). The results are presented in Table IV.

                  TABLE IV                                                        ______________________________________                                        Summary of Wash Test Results                                                                       Finished Pulp                                            Sample               Brightness                                               ______________________________________                                        C.sub.12-15 H.sub.25-31 O (EO)9.sub.H                                                              58.4                                                     C.sub.12-15 H.sub.25-31 O (EO)4.5 (PO).sub.7 H                                                     58.4                                                     Polymer A            61.3                                                     Polymer B-1          60.5                                                     ______________________________________                                    

As shown, it can be seen that the polymers of this invention producebrighter finished pulp.

It is apparent that many modifications and variations of this inventionas hereinabove set forth may be made without departing from the spiritand scope thereof. The specific embodiments are given by way of exampleonly and the invention is limited only by the terms of the appendedclaims.

What is claimed is:
 1. A deinking agent comprising a polyfunctional polymer of the formula ##STR18## wherein: ##STR19## R₇ is C₆ -C₂₂ alkyl phenol W and Y are independently H or C₁ -C₄ alkyl; and ##STR20## wherein M is ammonium or alkali metal; and a and b are positive integers of at least
 1. 